A new study tracking the health of responders to the September 11th terrorist attacks finds many suffered lung problems years later.

The study by Mount Sinai Medical Center's monitoring program examined more than 3,000 responders from 2004 to 2007.

The same individuals were examined between a year and three years after the attacks. The study shows more than a third had abnormal lung function on at least one exam.

Researchers say this proves persistent illness in people exposed to the toxic dust.

However, they acknowledge that those who participated in the study may have more health problems than those who chose not to enroll. They also point out that there is no information on lung function prior to dust exposure.

The news comes as several New York representatives have reintroduced a measure in Congress that would provide treatment and monitoring for September 11th responders.

Many Sept. 11 first responders - most of them cops, firemen and construction workers who took ill after working at Ground Zero - suffered lung problems more than five years later, according to a new study.

NEW YORK (AP) ? Researchers tracking Sept. 11 responders who became ill after working at the World Trade Center site found many had lung problems years later in a study the authors said proves persistent illness in people exposed to toxic dust caused by the twin towers' collapse.

The study by the Mount Sinai Medical Center's medical monitoring program examined more than 3,000 responders between 2004 and 2007, repeating exams conducted between the middle of 2002 and 2004.

Slightly more than 24 percent of the patients had abnormal lung function, the study found. In the earlier examinations, about 28 percent of the patients had similar results.

"We know people we are following are still sick. It's confirming what we've been seeing clinically," said Dr. Jacqueline M. Moline, who treats ailing responders and co-authored the study.

Experts have struggled since the 2001 attacks to find standards to define post-Sept. 11 illness and the time it would take to develop. The city's medical examiner recently added to the official victims' list a man who died in October of cancer and lung disease, citing his exposure to the dust cloud that enveloped the city when the 110-story towers collapsed.

Mount Sinai's program has treated more than 26,000 people who were at the site or worked there in the days after Sept. 11. The study's authors noted that participants asked to be enrolled in the program and may have more health problems than others who were exposed but didn't enroll.

But Norman H. Edelman, chief medical officer of the American Lung Association, said the study is "probably an important finding" of long-term post-Sept. 11 illness.

"The most reasonable explanation is that there's a subset of people who for whatever reason were more sensitive to the stuff that was inhaled," Edelman said.

The researchers tracked 3,160 people who took followup exams between September 2004 and December 2007; all had previous exams at least 18 months earlier.

The study appears in Thursday's editions of CHEST, a journal published by the American College of Chest Physicians.

NEW YORK, Feb. 5 -- Long after the towers of the World Trade Center went down in flames, workers there and first responders still suffer from decreased lung function, researchers here said.

Nearly a quarter of workers in a longitudinal study still had spirometric abnormalities at least 18 months after an initial examination, Gwen S. Skloot, M.D., of Mount Sinai, and colleagues reported in the February issue of CHEST.

"The increased prevalence of abnormal spirometry in follow-up examinations as long as five years after the Sept. 11 attacks makes long-term monitoring of World Trade Center responders essential," the researchers said.

Earlier studies found an initial high prevalence of decreased lung function after exposure, but this was the first study to look at post-Sept. 11 lung function changes over time. Action Points --------------------------------------------------------------------------------

Explain to interested patients that early studies found an initial high prevalence of decreased lung function in relief workers after exposure, but this study found problems remained nearly five years later in some cases.

Note that the most common problem was low forced vital capacity, although declines in lung function were not greater than had been expected.The most common problem was a low forced vital capacity (FVC), but the researchers said that overall, declines in lung function were not greater than had been expected.

The researchers followed 3,160 patients enrolled in the WTC Worker and Volunteer Medical Monitoring Program, which began in July 2002.

Each patient had a baseline and a follow-up examination at least 18 months apart, and both exams included spirometry, physical examination, chest radiography, and multiple standardized questionnaires.

During follow-up, there was a greater frequency of spirometric abnormalities in workers than in the general population.

About 24% had abnormal spirometry findings, the researchers said, with a low FVC being most common defect, occurring in 16.1% of patients at the second examination (at the first examination, 20% of patients had the defect).

"The high prevalence of a low FVC as the predominant spirometric abnormality is noteworthy," the researchers said, because it "may be due to airway inflammation, which may lead to reactive airway dysfunction syndrome (RADS) or chronic asthma, bronchiolitis obliterans, granulomatous lung disease, or other types of lung disease."

The researchers said that mean changes in prebronchodilator forced expiratory volume (FEV1) and FVC between the two examinations were 13 mL/year and 2 mL/year, respectively.

Bronchodilator responsiveness during the first examination and weight gain were the only statistically significant predictors of greater average decline in lung function between exams; however, these factors accounted for less than 10% of the variance.

Bronchodilator responsiveness during the first exam was associated with improved prebronchodilator spirometry during the next, and weight loss was associated with spirometric improvement, the researchers said.

The researchers concluded that because of the presence of spirometric abnormalities more than five years after the disaster in many exposed patients, "longer-term monitoring of World Trade Center workers is essential."

They noted several limitations, including self selection of patients, the absence of pre-exposure lung function results, and the absence of a control group of unexposed adults. They were unable to characterize workplace or home exposures to respiratory risks and they noted that longitudinal assessment of lung function using only two points in time can be contaminated with variability from measurement error.

THURSDAY, Feb. 5 (HealthDay News) -- Almost a quarter of a sample of people exposed to toxic dust after the Sept. 11, 2001, terror attack in New York City still suffer from diminished lung capacity, a new study finds.

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The rate of problems is much higher than normal, about 2.5 times more than would be expected in people who smoke, said study co-author Dr. Jacqueline Moline, director of the World Trade Center Medical Monitoring and Treatment Program Clinical Center.

"These tests confirm what we've seen clinically: People are sick, they're short of breath," Moline said. "They used to run miles a day, now they can barely run the length of a football field."

But it's not clear what all of this means for their health in the long term, the researchers said.

The study findings appear in the February issue of the journal Chest.

Experts estimate that about 40,000 people, including fire and rescue workers, were exposed to noxious pollution in the wake of the attack on the World Trade Center.

Between 2004 and 2007, researchers gave breath tests to 3,160 9/11 workers and volunteers who had taken part in an earlier round of tests from 2002 to 2004.

About a quarter of those tested still have limited lung capacity and lung function, Moline said. "The most common finding we see is that people aren't able to take in as deep of a breath as you'd expect, and some can't push it out as much."

The normal rate of lung capacity problems for a similar group of people would be five percent for non-smokers and 10 percent for smokers, she noted.

"These are problems we're seeing five or six or seven years after the towers fell," Moline said. "Many of these folks are going to have long-term problems, and their lung function won't return to normal."

She said that researchers may never know what component of the toxic brew of 9/11 dust and smoke hurt the lungs of those who responded to the emergency.

Workers at the site reported cases of a signature "World Trade Center cough" and many said they suffered from such symptoms as itchy eyes and runny noses, even after the site cleanup ended in 2006.

The news is not all bad, however. Medication and other treatment could help those who were exposed, Moline said.

Dr. Norman Edelman, chief medical officer of the American Lung Association, said that researchers still need to figure out what comes next for those exposed to the pollution.

"We don't know what it means for future health so we must, as the authors suggest, continue to follow them," he said.

Research released in September by the New York City health department looked at a wide range of people exposed to the World Trade Center disaster, including nearby residents and commuters. Authors of that study estimated that more than 400,000 people were exposed to the disaster. An estimated 35,000 to 70,000 of them developed post-traumatic stress disorder, and 3,800 to 12,600 people developed asthma as a result.

More information

Find out more about the health of people exposed to the 9/11 attack at the World Trade Center Health Registry.